This is a biobehavioral, longitudinal investigation of the role of emotion in the development of psychopathology in adolescence. The focus is on (a) the role of multiple components of negative emotions (anger, anxiety, sadness) in the evolution of psychopathology, and (b) socialization experiences and biological processes that contribute to emotion dysregulation and disorder. The dysregulated experience and expression of emotion is implicated in both externalizing (antisocial patterns) and internalizing (anxiety, depressed mood) disorders. Adolescence is a critical juncture in the development of these disorders. The incidence of psychopathology increases during this time period, and clinical problems become more differentiated along gender lines, i.e. more antisocial behavior in males and more anxiety and depression in females. Four groups of youths are studied: (1)comorbid externalizing and internalizing problems, (2)externalizing problems, (3) internalizing problems, and (4) asymptomatic. Youth range in age from 11 to 16 years and are studied at two time points, spaced two years apart. Equal numbers of males and females are studied in order to examine etiology of sex differences in symptoms, emotion regulation, and developmental changes in how disorders manifested. During the past year data collection was completed for Time 1. This year will be spent (a) coding, analyzing, and preparing articles for publication based on Time 1 data, and (b) collecting the Time 2 data for longitudinal analyses. One article on neuroendocrine responses to stress has been accepted for publication. Characteristic diurnal patterns for cortisol were observed: there was a marked drop by late morning and a further reduction by late afternoon. These decrements were present for both males and females in risk and control groups. During an anxiety induction task, increases in cortisol levels were seen only in internalizing girls. This is of interest, given that the strong sex differences in adult depression (higher in females)begin in adolescence, suggesting a possible physiological substrate.